Adding end-to-end tests

The first test is testing a tricky cache scenario with the back when testing variables.
The end-to-end package used is testcafe.

tests/tests/test.ts

@@ -0,0 +1,41 @@
+const fs = require('fs')
+
+fixture `Variables`
+    .page `http://play.workadventure.localhost/_/global/maps.workadventure.localhost/tests/Variables/Cache/variables_tmp.json`;
+
+test("Test that variables cache in the back don't prevent setting a variable in case the map changes", async t => {
+    // Let's start by visiting a map that DOES not have the variable.
+    fs.copyFileSync('../maps/tests/Variables/Cache/variables_cache_1.json', '../maps/tests/Variables/Cache/variables_tmp.json');
+
+    await t
+        .typeText('input[name="loginSceneName"]', 'foo')
+        .click('button.loginSceneFormSubmit')
+        .click('button.selectCharacterButtonRight')
+        .click('button.selectCharacterButtonRight')
+        .click('button.selectCharacterSceneFormSubmit')
+        .click('button.letsgo');
+        //.takeScreenshot('before_switch.png');
+
+    // Let's REPLACE the map by a map that has a new variable
+    // At this point, the back server contains a cache of the old map (with no variables)
+    fs.copyFileSync('../maps/tests/Variables/Cache/variables_cache_2.json', '../maps/tests/Variables/Cache/variables_tmp.json');
+    await t.openWindow('http://play.workadventure.localhost/_/global/maps.workadventure.localhost/tests/Variables/Cache/variables_tmp.json');
+
+    await t.resizeWindow(960, 800);
+
+    await t
+        .typeText('input[name="loginSceneName"]', 'foo')
+        .click('button.loginSceneFormSubmit')
+        .click('button.selectCharacterButtonRight')
+        .click('button.selectCharacterButtonRight')
+        .click('button.selectCharacterSceneFormSubmit')
+        .click('button.letsgo');
+        //.takeScreenshot('after_switch.png');
+
+    const messages = await t.getBrowserConsoleMessages();
+
+    const logs = messages['log'];
+    const lastMessage = logs.pop();
+    // Let's check we successfully manage to save the variable value.
+    await t.expect(lastMessage).eql('SUCCESS!');
+});